Stratification of patients for coronary angiography: Fragmented QRS complexes – a marker of severity?

The possibility that particular alterations on a standard electrocardiogram (ECG) can reveal the existence of areas of myocardial fibrosis could be of clinical interest, not only for non-invasive detection of obstructive coronary disease, but also as an easily accessible risk marker that can be assessed without the need for more complex and costly exams.The presence of pathological Q waves on the ECG has long been used in clinical practice to identify scarring from previous transmural myocardial infarction (MI).However, this sign has low sensitivity, since it may not initially appear (non-Q-wave MI) or may sooner or later disappear, and so the absence of Q waves does not exclude the possibility of fibrous scarring of the myocardium.There have therefore been efforts for many years to discover alterations in the morphology of the QRS complex that can reliably identify the presence of myocardial scarring.Examples include the investigation by Flowers et al. 1 in the 1960s of high-frequency components of the QRS, which the authors discovered to be more common in patients with previous MI, a finding subsequently confirmed by Das et al. 2 in single-photon emission computed tomography